Re: Can imagemagick really be safely purged or removed?
On Mon, 30 Oct 2017 23:13:33 +1300
Richard Hector <email@example.com> wrote:
> On 30/10/17 15:46, Celejar wrote:
> > On Sun, 29 Oct 2017 08:28:46 -0400
> > The Wanderer <firstname.lastname@example.org> wrote:
> >> On 2017-10-29 at 07:49, Jörg-Volker Peetz wrote:
> >>> Celejar wrote on 10/24/17 15:09:
> >>>> On Tue, 24 Oct 2017 08:52:46 +0200
> >>>> Jörg-Volker Peetz <email@example.com> wrote:
> >>>>> I forgot that you showed the dependency on cups-filters in your original mail.
> >>>>> On testing cups-filters 1.17.9-1 does not depend on imagemagick, it only
> >>>>> recommends it. And I use APT::Install-Recommends "false"; in /etc/apt/apt.conf.
> >>>>> Therefore, on this system imagemagick could be removed.
> >>>> Interesting, thanks. So they changed the dependency from 'depends' to
> >>>> 'recommends', but they're still 'recommending' a dummy package.
> >>> Taking another look at package imagemagick-6.q16 (version 8:18.104.22.168+dfsg-16) it
> >>> states that it provides imagemagick. Therefore, I don't understand what's going
> >>> on on your system and there's nothing wrong with package cups-filters, I think.
> >> My guess involves vague memories of there being an issue with versioned
> >> Provides: - although I thought that was more "you can't Provides: a
> >> specific version", not "a versioned Depends: won't be satisfied by a
> >> Provides: from a package with a suitable version number".
> > I don't understand this stuff well enough to add anything to the
> > conversation. All I know is that I still can't remove imagemagick
> > despite the fact that imagemagick-6.q16 "Provides:" imagemagick.
> > Celejar
> imagemagick-6.q16 Provides: imagemagick, but not a specific version
> cups-filters Depends: imagemagick (>= 6.4~)
> The real imagemagick package is at 8:22.214.171.124+dfsg-11+deb9u1 (on my
> machine anyway), which satisifies the cups-filters dependency.
> The system doesn't know whether the version of imagemagick Provided by
> imagemagick-6.q16 is new enough, so you still need the real package.
Ah, thank you. I couldn't find the whole Depends: / Provides: rules
clearly documented anywhere, but that certainly explains it. So either
imagemagick-6.q16 should be more specific about which version of
imagemagick it "Provides:", or, if that's not possible (as per
Wanderer's suggestion), then cups-filter needs the 'imagemagick'
package, and it's not quite a dummy that can be removed.